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SSDs are not the cache that would be battery backed. So I'm not following completely. If you don't have an NV cache or a BB cache then you need that in front of the SSDs to feed the SSDs. The data will be lost in your regular cache because it will never hit the SSDs.

I'm wondering how "safe" it is to run a CacheCade Pro 2.0 Write Back cache w/ 2x SSDs (RAID1) with no BBU on an LSI 9270-8i MegaRAID card?

My thinking is that as the SSDs are non-volatile storage this eliminates the need for a BBU as once power is restored the 9270 should commit the remaining in the SSDs data to the HDD back end?

Any advice welcome,

Cheers,

Myles

BBU is a stone age. It does not really protect from anything. Run clustered (multiple controllers) with huge UPS for every single I/O gateway node. That's safe way. BBU is half ass solution to say @ least.

I'm wondering how "safe" it is to run a CacheCade Pro 2.0 Write Back cache w/ 2x SSDs (RAID1) with no BBU on an LSI 9270-8i MegaRAID card?

My thinking is that as the SSDs are non-volatile storage this eliminates the need for a BBU as once power is restored the 9270 should commit the remaining in the SSDs data to the HDD back end?

Any advice welcome,

Cheers,

Myles

BBU is a stone age. It does not really protect from anything. Run clustered (multiple controllers) with huge UPS for every single I/O gateway node. That's safe way. BBU is half ass solution to say @ least.

For those who think that this sounds crazy, this has long been how big iron handles this. Mainframe and other large scale, super reliable compute environments base their systems on assuming that power will not be disrupted rather than trying to built reliable power into the inside of the chassis. IBM, Oracle and Fujitsu being key examples. They feel, and basically the entire industry agrees, that facilities needs to deliver power externally not have the IT department addressing power at the server or component level. It's much better for every component if power is made reliable rather than trying to make servers be reliable when power is unreliable.

I'm wondering how "safe" it is to run a CacheCade Pro 2.0 Write Back cache w/ 2x SSDs (RAID1) with no BBU on an LSI 9270-8i MegaRAID card?

My thinking is that as the SSDs are non-volatile storage this eliminates the need for a BBU as once power is restored the 9270 should commit the remaining in the SSDs data to the HDD back end?

Any advice welcome,

Cheers,

Myles

BBU is a stone age. It does not really protect from anything. Run clustered (multiple controllers) with huge UPS for every single I/O gateway node. That's safe way. BBU is half ass solution to say @ least.

For those who think that this sounds crazy, this has long been how big iron handles this. Mainframe and other large scale, super reliable compute environments base their systems on assuming that power will not be disrupted rather than trying to built reliable power into the inside of the chassis. IBM, Oracle and Fujitsu being key examples. They feel, and basically the entire industry agrees, that facilities needs to deliver power externally not have the IT department addressing power at the server or component level. It's much better for every component if power is made reliable rather than trying to make servers be reliable when power is unreliable.

100% Agree. I've seen some ancient servers run for a decade, because they had 100% Clean and consistent power/air.

"Datacenters" that experience constant cooling/power fluctuations murder drives/data. That said, a lot of people are not willing to spend 2K per rack per month to have this level of resiliency.

As if it's NV then the BBU is redundant and running WB-Cache should be a non-issue.

SSDs are NV by nature and never battery backed. The cache, though, (the RAID cache, not the higher level CacheCade) is RAM and can be NV/Flash or volatile traditional RAM and require battery backing. So that is where the question resides. That you use SSDs is a red herring really in the equation unless, as we mentioned, the regular cache is bypassed which I find extremely unlikely.

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